The Static Pressure Regulating Damper, Model SPRD, is a single blade, counter balanced weighted damper, that operates on air pressure in order to control the flow of by-pass air on a zoned system. SPRD dampers are available in both rectangular/square and round sizes. The SPRD has an adjustable arm and weight to maintain the correct amount of pressure in the duct system. The SPRDs can be mounted in both horizontal and the vertical position for either up flow or down flow systems. The SPRD can also be used as a back draft damper to relieve excess air pressure in any duct system.